Telephone-exchange system.



B. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1906.

1,107,143. Patented Aug". 11, 1914.

16 SHEETS-SHBET 1.

1 P m z Snuznfoz 19i Hum:

E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION TILED MAR.16,190&

1,107,143, Patented 'Aug.11,1914.

16 BHEETS-SHEET 2.

E. E CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1906.

1,107,143, I 1 PatentedAug m1L1914.

16 SHEETSSHEET 3.

Wifiaanreav lid/811,074

E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1906.

Patented Aug. 11,1914,

16 SHEETSSHEET 4.

E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED 11 111.15, 1906.

Patented Aug. 11, 1914,

16 sHBETs sHEBT 5.

E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR..15, 1906. 1,107,143. Patented Aug. 11, 191 1 16 SHEETS-SHEET 6.

E. B. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1906.

Patented Aug. 11, 1914,

16 SHEBTSSHEET I.

fig. 55.

Swuzwtoz E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLIGATION FILED MAR.15, 1906.

1,107,143. Patented Aug. 11, 1914,

16 SHEETS-SHEET 8.

. Illllill- 4 gawentoz Wit one;

E. B. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 15, 1906 1,107,143. v Patented Aug. 11,1914

1 6 SHBBTSSHEET 9.

lawzntoz Witnesses E. E. OLEMEN'L.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1901a Patented Aug. 11, 19m

16 SHEETS-SHEET 10.

animator E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAR. 15, 1906.

1,107,143. Patente ad Aug. 11, 19m

16 SHEETBSHBET 11.

E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED MAR. 15, 1906.

Patented Aug. 11, 1911 16 SHEETSSHEET 12.

E. E. CLEMENT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 190s.

Patented Aug. 11,1914.

1G $HEETS-SHEET l3. & M

Pip U fiwuzar- E. E. CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION TILED MAB.15, 190a.

Patented Aug. 11, 1914.

16 SHBETSSHBET 14- lmh E. E. CLEMENT. I TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.15, 1906.

1,107, 143, Patented Aug. 11, 1914.

16 SHEETSSHEET15 I atwentoz Witueoaga E. El CLEMENT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.16,1006.

' 1,107,143. Patented Aug. 11,191

l6 SHEETSSHEET 16.

awwwcoz UNKTED STAlllS OFFICE.

nnwnnn n CLEMENTMOF wasnmeron, exercise or COLUMBIA, ASSIGNQR, BY

' rtssnn assrcnMENTsr-Tornnnnmm QJSTEiiElIfiJD-Ei mo N R Specification of Letters Patent. Patented Aug. 11, 1914.

Application filed March 15, 1906. Serial No..306,292.

To all whom it may concern:

Be it known that I, EDWARD E. CLEMENT, a citizen of the United States, residing at Washington, inthe District of Columbia, have inventedcertain new and useful Improvements in Telephone- Exchange terns, of which the following is a specification, reference being bad therein tov the accompanying drawing.

My invention relates to telephone exchange systems, and has for its object the improvement of such systems in point of efficiency and economy. In order to attain this object I employ a combination of apparatus, a portion of which is manipulated by operators. and other portions are automatic in their action.

Briefly stated, my present invention comprises the following elements: Subscribers stations equipped merely with telephone talking and signal-receiving sets,'of the ordinary or any desired type used in manual systems; line-circuits connecting these sub-' stations-and a central ofli'ce and there carried to what I shall call my relay-primaryselector sets, being multipled into a number of these sets; dummy trunks terminating each in a relay primary selector set, and adapted to be connected automatically there-- by to a subscribers line when calling; automutic switches less in number than the number of lines, a set oi these switches being connected to each dummy trunk; a signal impulse generator common to all the apparatus: operators signaling keys associated with the dummy trunks adapted to connect the impulse generator thereto; and finally multiple-contacts for the subscriliiers lines in the banks of the automatic connector switches.

Stated in similarly brief terms, the operation of this system is as follows: Assuming the subscribers to be supplied with current from a common battery at the central ofiicc, a subscriber calls by removing his receiver from the hook in the usualmanner, thereby energizing certain of the primary selector relays of his set, which inoperetiny, automatically connect his line to an idle dummy trunk and set a signal before the operator to whom that trunk belongs. The operator may have a listening key. or may be automatically connected to this trunk when the signal is set, and she thereupon ascertains from the subscriber. the number i wanted;

She then. sets her signaling keys or buttons in. accordance with said number, thereby connecting the main impulse generator to the automatic switches, so as to send a proper succession of'impulses to operate the: switches to select the line wanted, and totest and ring the same. tors keys preferably more push-buttons fitted with latches, and arranged in sets of ten.

The operators work isthus reduced to getting the number and pressing the proper buttons. 1

The underlying principles oi which I have made use in this invention sufiiciently appear from the foregoing statement. and will be claimed broadly in their application. The amount of detail involved in a system ofthis character. all of which it is necessary to exfplain'in order to make a complete disclosure, is so great that there is of course; some danger of appearing to limit the in ventionuto specific arrangements which in fact may be varied without changing the principles involved. It is to be understood that for the sake of olearness I shall make the following detailed description absolutely specific, but do not mean to limit myself thereby to such specific disclosure only.

My invention is illustrated in the accompanying drawings. in which F igures 1 to 8, inclusive, constitute when put together a continuous diagram of one complete embodiment of my invention. Of these. Fig. 1. shows the sul' scribers stations and lines. Figs. 2 3 and 4t show portions of three primary selector sets; Fig. 5 shows three trunks, and operating relays, with three different arrangements, Fig. 5 two others. Fig. 5" shows three trunks all hav ing a uniform arrangement. similar to that of the upper trunk in Fig; 5. Fig. 6 shows set of signaling buttons and an impulse generator therefor to work with Figs. 5 or 5. Figs? and 8 show the automatic switch circuits; Figs. 9 and 1'0 are respectively a side and top plan view of a ten point relay used in my system; Fig. 11' is a front View and Fig. 11 is a bottom plan view of a typical automatic switch which maybe employed, and which is illustrated for descriptive purposes only; Fig. 12 is a condensed diagram of a primary selector set; Fig. 13 is a diagram of a modified arrangement of sending; buttons and impulse generator,

Simona tlittshown iirFig. 6 rand Fig; Le-

I make the oberacured at the rear end of the n, of the armature,-

shows a modified arrangement of trunk circuits to cooperate therewith. Fig. 15 is a diagram of a secondary selector set governed by the trunk relays, for automatically connecting the operators to trunks.

Before proceeding to the circuits, Wherein the invention in the present case resides, it will be advisable to obtain a clear understanding of the types of apparatus which I employ, and which are shown in Figs. 9 to 11 inclusive. I do not give any special illustration of a single point or ordinary relay, for the reason that everyone skilled in the art is so familiar with these devices as to render it unnecessary. That portion of my system which is illustrated in Figs. 2, 3 and 4 constitutes what I have termed the primary selector or answering portion of the system. In this appear a number of ten point relays and a number of single point or-ordinary relays. These latter may be of any suitable type. The only special feature required is that of double Winding, which, as I shall point out hereinafter, can be dispensed with if some other means be provided for locking the relays when energized. The apparatus at the subscribers stations also forms no part in itself of invention, except as it co-acts With the apparatus and circuits at the central office. I contemplate using an ordinary common battery telephone outfit the same as those employed in standard manual switchboard systems.

Referring then to Figs. 9 and 10, I will briefly describe the ten point relay, N. This comprises an iron back yoke, 92, a pair of magnets, n, mounted thereon, an armature, n extending across the front end thereof, and a set of contactsprings, n, n, n, a, overlying the upper bell-crank extension of the armature, so as to be worked thereby. There are eleven sets of these springs, all serelay upon the return portion, a, of the back yoke. The front ends or pole pieces of the cores of the elec'tro-magnets, a, receive the front yoke, a of non-magnetic material, such as brass, this also having an upper return'portion, n",

overlying the magnet windings, and alined' with the return portion, mi, of the back yoke, a. Upon this return portion, a, of the front yoke the upper bell-crank arm, of, lies fiat under normal' conditions. Cut from end to end of this upper bell-crank portion, a", are two grooves in which rest the insulating studs of the spring sets. The function of these slotswith thest'uds resting in them is to retain the armature in place. At their front ends the springs are separated by shouldered studs, the lowermost stud of each pair resting upon the armature, carrying the lower spring of its pair, a, on its shoulder, and the upper spring, a, on its head, its

through a hole in the spring, a.

my presentfrom the description of Strowger switches. As I have previously trunk and switch stem passing through a hole in the spring. a, while the uppermost stud of each pair rests upon the spring, 12., supports the spring. or, upon its shoulder, and carries the spring. a, on its head, its stem passing The actuating studs a fleet only the springs, It, a, of each set, these constituting the movable springs, while the others, a, a, are fixed. Each actuating stud carries the spring, a", on its shoulder, and the spring, a, on its head, its stem passing through holes in the springs, a a.

The entire relay is secured to an insulating back block, a, by means of the bolts, n3, constituting extensions of the cores and threaded to receive lock-nuts. The rear ends of the contact-springs extend out through openings made in this block, and an inclosiug shell or casing, 11". is fitted to the block. with which it forms a. light joint all around the edge. This shell is secured in place by means of the stud, n, threaded to receive the nuts. a. As the armature. 11 is at tracted, the springs. 91., u, are lifted by the actuating-shah until their outer points make contact with the corrcspoiuling points of the springs, n",

a, in each set. Ten of these sets are line-contacts, and the eleventh is for locking purposes, as will suliiciently appear the Circuits. Referring now to Figs. 11 and 11. I have therein shown a piece of apparatus which I do not present as a part of my invention,

nor as an example of finished design in an automatic switch. but which is typical of the class of switches commonly known as or automatic electric pointed out, my present invention may be practised with various connecting means, but in order to render this description complete and coherent, I include this form of switch and its circuits.

As illustrated in l igs. 11 and ll the switch is designated in toto by the letter S, and represents of the in tern'iediatc a selector switch. that is one switch units to transfer a connection from the calling line to an idle in the desired thousands or hundreds group. It has a frame, a, provided with two posts, 8', extending downwardly to support the contact-banks, a, s", which as shown in Fig. ll are arranged in an arc-shaped figure around the central spindle, There are ten rows in each contact-bank, with ten pairs of contacts in each row of the bank, 8 and ten single contacts in each row of the bank, a. The contacts are radial strips of brass or German silver clamped solidly between upper and lower plates. 8, and separated by suitable insulation. Upon the spindle are. mounted the wipers, s, s, a the latter being a connected pair adapted to rubngainst both faces of the single contacts in the banks, a, and the former being separate wipers adapted to rub upon opposite faces of the pairs of,contacts in thebank, .9". Connection is established with these wiper springs through a. flexible cord or similar means, which I have not deemed it necessary to show.

- The spindle, s, is av long straight piece of steel, journaled in the upper and lower members of the frame, 8, so that it can both turn and slide therein. Its own weight normally keeps it down in the position shown in Fig. 11, with the wipers out of alinement with any of the contacts. The parts are not drawn to scale, but it is supposed that the first upward step. of the spindle produced in the operation of the vertical magnet will bring the wipers opposite the respective first rows of contacts in the banks, and each sue cessive step upward will shift the wipers opposite another row. After being stepped up until the wipers are opposite the-desired rows, the spindle is then supposed to be turned one step at a time by the rotary magnet until the wipers rest upon the contacts of an idle trunk. For the purpose of eifecting these vertical and rotary movements, the spindle carries two ratchets, 8, 8 the former having a number of annular teeth, usually eleven or twelve, and the latter having a circular series of vertical straight teeth, which usually do not extend entirely around the ratchet surface, but only far enough to carry the are through which the wipers mustsweep when passing over all the contacts in a row. The vertical movement of the spindle is eflected by the magnet, o, and the rotary'movenient by the magnet, 1', both being mounted on the frame. The magnet, v, has an armature, w, drawn down by a spring, v and carrying a pivoted pawl,

n, provided with a tail spring, a, which tends to throw the tip of the pawl into engagement with the ratchet, a", but is normally i'irevenicd from doing so by the stop pin, a, set in the back plate, a, which is supposed to cover the entire back part of the frame, a. When the magnet, w, is energized it draws up its armature. 'v', and the point of the pawl, a, is immediately thrown forward to engage the upper tooth of the ratchet, s, the continued upward motion of the armature then raising the spindle and its wipers one step. The rotary magnet, 1', has an armature. 'r, appearing edgewise to the observer, in Fig. 11, and pivoted at its nearest edge in a vertical. line, so that the edge away from the observer swings to and from the magnet poles, moving the extended arm,

1' back and forth, and by means of the terminal pawl, r turning the ratchet, s the pawl normally being retracted by the spring, 1'.

In order to retain the spindle in any position to which it may be raised and turned by the magnets, w, and 1', I provide a pair of swinging awls, t, t, whose ends engage the respective ratchets, 3 and s, and whose bell-crank body, 25 is pivoted between posts,

25*, at the ed ge farthest from the observer. Upon the front edge of the body is a projecting pin, 6, adapted to be engaged by the link, '27, on the upper end of the armature lever, .t, of the release magnet t. The link and the lever are normally drawn over by thespring, t, into the position shown in Fig. 11. The pawls t, 15 are normally held in engagement with their respective ratchets by a suitable spring, not shown. When the magnet, 25, is energized it draws over the lower end of the armature lever, z to the right, throws the link, t, to the left until it passes over and engages the pin. 25, and when the magnet is again deinergized the spring, it, again draws the link to the right and swings the bell-crank body, it, upon its pivots so as to raise the pawls. t, F, from their ratchets and permit the spindle to be rotated so as to disengage the wipers, s, s", 8 from the rows of contacts and then to drop into the normal position of disuse. These are the operating members of the switch. In addition, the switch frame carries an esca 'iement and its controlling magnet for the side switch and for certain contacts which will be specified in the description of the circuits. The side switch is shown in front view in Fig. 11, at it. It consists of a plurality of switch-arms mounted one over the other with interposed insulation, the entire set being carried upon a lever, a, pivoted at 11 and normally held in the position shown. against the tension of the spring, a, by the engagement of the up per end, a, with the first one of a number of teeth, 7.1/ carried upon the arnniture lever, a, and constituting an escapementb \Vhenever the magnet, U, is energized the lever, u, is thrown over to the left, the tip, 0.1. passing a. fractional step to the right. When the armature is again retracted the tip passes a full step to the right, and so on, these steps placing the arms, u, successively in contact with the first, second and third sets of fixed contact points, 1/7, on an insulating block carried by the fame. When the switch spindle is all the way down in its normal position the lower edge of the ratchet. wheel,

8 engages the short upper arm of the bellcrank lever, u whose lower arm engages the lever, u, to push the same back into initial position as shown in the figure.

The magnet, U, at certain times has its armature mechanically held up, and for this purpose a projecting finger, r, is attached to the armature, 7-, of the rotary magnet, 1 Upon the upper part of this finger a button of insulating material is placed to engage and normally keep closed a pair of contacts, 9', in. the circuit of the magnet, r.

v wipers. The magnet,

down, the line-circuit- These contacts and the projecti finger 1', are used only in the selector switc 1, in which the rotary movement is accomplished by constant and automatic vibrations of the armature r, until an idle trunk is found by the U, controls a. set of contact springs u it, the former normally closed, and the latter normally open. When the armature, u", is attracted the conditions of these springs are reversed.

In order to restore the spindle to its normal position in a rotary direction, a coiled spring is provided housed in a cap a, at the top of the spindle, one end of the spring being attached to the same, and the other end to a lever arm, a, loosely journaled at one end on the spindle between the cap and the collar, 8 and loosely sliding at the other end on apost, s. The collar, 8 carriesthe stop arm, a, which abuts against a turned down leaf on the arm, 8 when the parts are in normal position, the tension of the spring thus being carried by a pressure of the arm 8 upon the turned down leaf on the arm 8 and the arm .9 surrounding the post sfithus being relieved of any rotational pressure against the post 8 and being thus placed in position to slide vertically upon the post a with little or no friction. The travel of the arm, 8 up and down the fixed post, 8 and the vertical extension of the ratchet, e enable the spindle to be turned and restored through its full sweep when in any previously assumed vertical position.

Having thus described the mechanical parts a knowledge of which is essential to the comprehension of my circuits. I turn to the description of the latter, beginning with Fig. 1. Therein I have shown three subscribers stations, A, A, A each equipped with a telephone transmitter, a receiver, a switch-hook, a ringer, and condenser, all of usual or suitable type for use with common battery circuits. When the hook is up, that is when it is relieved of the weight of the receiver, the circuit is through the transmitter and receiver; and when the hook is is completed for alternating current only, through the ringer and condenser. Since the circuits are the same for all the lines, I- will refer to the line from station A only. This consists of conductors 1 and 2, extending from the substation to the central oflice. At the sub station the talking circuit is completed throu h the wires 3% when the hook is up, and t e ringing circuit through the wires 56 when the hook is down. These figures are useful for the purpose of tracing the circuits only.

Turning now to Fig. 2, the line-wires 1 and 2 appear at the left hand side of the figure, terminating in contacts of the cutoff relays M, whichare normally deenergized,

so that in each case the line-wire 2 is grounded at 7 and the line-wire 1 extended through line 8 to the linc-relay M, and so to main battery B and grcmnd. The armature, m, of each line-relay M is groum'lcd at 9, and when attracted is adapted to close upon terminal contacts of wires leading to the tens and units relays of the rimary selector sets. I preferably divide a l the incoming lines in an exchange into groups of say one hundred each, andto each group I apportion a fixed number of trunks leading to connective apparatus. In a small or comparatively inactive exchange the percentage of these trunks may be as low as live, and in busy exchanges it may be raised to ten or even fifteen. I assume, however, that ten per cent. of connective apparatus will be suficient to care for the present system, hence I provide ton trunks for each one hundred lines, and a complete set of lens and units relays in a primary selector group for each trunk. The circuits herein illustrated show six lines, which for C(JIIVGIllQIlCO I will call Nos. 500, 501 and 502 (Fig. 2) and 510, 511 and 512 (Fig. 3). The subscribers circuits of Fig. 1 will fit any of these, and in order to fully comprehend the connections of these lines and the arrangement of the tens and units relays, it is necessary to consider Figs. 2, 3 and 4 together. In l igs. 2 and 3 the subscribers extension lines are shown coming into their initial terminals on the tens relays, which are of the type shown in Figs. 9 and 10. Each of these relays carries'the terminals of ten lines, and for each trunk there are ten of these relays, so that for 100 lines, provided with ten trunks, there will be 100 ten point relays, containing 1,000 line-terminals; from which it appears that each line can be multipled ten times, which it should be in order to obtain access on occasion to every one of the ten trunks. The contacts on the ten point relays are arranged in duplicate pairs. That is, the incoming lines terminate each on one pair of springs, opposite which another pair of springs ap pears to which the line is connected when the relay is energized, and from which a local circuit passes to the front contact springs of a particular units relay or single point relay. For each group of ten tens relays there are ten units relays, or twenty relays in all for each trunk. A group of this kind constituting one primary selector or dummy trunk terminal for thirty lines. is shown in Fig. 12, apart from the other figures, so as to free the lines from their multiple connections. In order to make clear the connection of a line coming into the exchange, I will first refer to this figure and then trace the circuits through the others.

In Fig. 12, N, N, N, are three relays of the type shown in Figs. 9 and 10, having ten .pairs of contacts each for the line-circuits. 

